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1.
该文运用SCF-MO AM1方法,通过能量梯度全优化计算,求得了硝酸乙酯的反式和傍式两种分子构象,两种构象间的能量差为3.51kj/mol。傍式比反式稳定,反式-傍式旋转势垒为2.34kj/mol。由AM1法计算,制作了硝酸乙酯的碱性SN2水解位能曲线,求得活化能为63.60kj/mol。讨论了水解过程中反应体系的几何和电荷分布的变化规律。  相似文献   

2.
给出了差分方程un+r=∑n+ri=1aiun+r-i+bnui=cii=0,1,…,r-1{的一个显示解un=dn+∑ni=1dn-i∑k1+2k2+…+iki∑ij=1kj!∏ij=1akjj∏ij=1kj!  相似文献   

3.
关于差分方程un+r=Σ(n+r,i=1)aiun+r—i—bn的显示解   总被引:4,自引:0,他引:4  
给出了差分方程{un+r=Σ(n+r,i=iaiun+r-i+bn ui=ci i=0,1,…,r-1的一个显示解,un=dn+Σ(n,i=dnik+k+2…+iki(Σ(i,j=1kj)!Π(i,j=1)aikj/Π(i,j=1)kj!.  相似文献   

4.
温度对Cr2O7^2—阳极形成过程的影响   总被引:1,自引:0,他引:1  
用分解极化曲线法研究了在0.1mol/LCr2(SO4)3+1mol/LNa2SO4溶液中Pt和PbO2电极上Cr2O7^2-阳极形成和O2析出过程中温度的影响。实验结果表明,在1.95V下,Pt电极上O2和Cr2O7^2-的表观活化能分别为57.4kj/mol和61.3kj/mol;PbO2电极上O2和Cr2O7^2-表观活化能分别为40.2kj/mol和46.2kj/mol。温度对于Cr2O7  相似文献   

5.
考虑如下的抛物型方程(1)有限差分逼近于(1)是(2) _t其中a是一个常数(0≤α≤1),α+β=1.令τ/h2=γ=Const,当τ,h→0。 我们假设在网格点(xk,tj)上,差分方程(2)的截断误差为Ekj,微分方程(1)的准确解为Ukj,有 限差分方程(2)的准确解是ukj,逼近误差是εkj=Ukj-ukj。我们记其中,A,B是n×n的三对角矩阵,我们建立了下面的定理定理1: 对任何固定 ,假如 ,其中Si是下面方程的解。定理2:假如  ,则有;假如  ,则,此时差分方程(2)依范数 稳定。  相似文献   

6.
三种弹涂鱼的生化组成及能值分析   总被引:16,自引:3,他引:16  
测定了三种弹涂鱼肌肉的蛋白质,脂类和糖类的组成以及能值,分析了其氨酸的种类及其比例,结果表明:1)蛋白质三种弹涂鱼最主要的生化物质,含量占鱼体湿重的6.685%~9.891%;2)三种鱼的比能值,能量与蛋白质的比值均不高,分别为3.044~4.249kj/g和39.873~45.535kj/g;3)蛋白质中氨基酸的种类齐全,不同种鱼及雌雄个体物各种氨基酸含量差异不大,必需氨基酸的含量较高,占总氨基  相似文献   

7.
利用等参变换、在局部有限单元上近似Jacobi行列式p(x)及系数qi(ξ,u),1≤i≤k等方法,对非矩形区域上非线性抛物型方程组qi(ξ,u)uit-∑kj=1·(a~ij(ξ,u)uj)+∑kj=1b~→ij(ξ,u)·uj=fi(ξ,t,u),1≤i≤k,提出了一类方向交替Galerkin格式,并得到最优的L2-和H1-误差估计.  相似文献   

8.
Reich的一个定理改进及其相关问题   总被引:3,自引:3,他引:0  
设f为关于ψ0的Teichmuller映照,若存在函数列{ψn}包含β(Ω),使得lim/n→∞ψn(z)=ψ0(z),a.e.,lim/n→∞∮「k|ψn|-Re(kjψn)」d.xdy=0,其中kj为f的复特征,Reich证明f是唯一极值映照,在此基础上,证明去掉f为Teichmuller映照这一假设,Reich的结论仍成立,文中还得到在一定条件下,Reich这一结论的逆命题也成立。  相似文献   

9.
用热分析法研究半焦气化动力学   总被引:3,自引:0,他引:3  
使用等温热重法,对鞍山钢铁公司高炉喷吹用的城子河烟煤制得的半焦气化动力学特性作了研究,并与焦炭的反应性作了比较。研究表明,半焦的反应性优于焦炭,半焦的气化反应是由气体的内扩散控制的,相应的表现内扩散活化能力为136.83kj/mol,并得出了半焦气化的动力学模型。模型预测值与实测值有很好的一致性。  相似文献   

10.
给出在室温C60-甲苯溶液聚结速率与浓度的关系为二级。在温度为25-30℃范围,C60-甲苯饱和溶液的聚结动力学可用Smoluchowski快速聚结动力学描述,求得输运活化能为11.2kj.mol^-1。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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